1. Field of the Invention
The present invention relates to a flow rate control device having a priming mechanism. More particularly, the present invention relates to a flow rate control device capable of instantaneously priming a tube on the downstream side of the device by pressing a reservoir encased therein. The flow rate control device of the present invention is particularly suitable for use with a ballooned liquid medicine continuous injector. Such an injector is used as a means for administering an analgesic, an anesthetic, an antibiotic, a carcinostatic agent into blood vessels, and the like continuously and in a small amount by injecting liquid medicine filled in a balloon made of an elastomeric material by the contracting force of the balloon.
2. Description of Related Art
In recent years a ballooned medicine continuous injector has been used as a means of administering an analgesic, an anesthetic, an antibiotic, a carcinostatic agent into blood vessels, and hypodermic portions and epidural portions or the like continuously and in a small amount (Japanese Examined Patent Publication No. JP-A-62-501333, Japanese Unexamined Patent Publication No. JP-A-5-237194 and the like). To use the injector, it is necessary to first fill the liquid medicine in a tube and prime the tube to vent the inside air before injecting the liquid medicine into a patient.
In the liquid medicine continuous injector of Japanese Examined Patent Publication No. JP-A-62-501333, a flow rate control tube is provided adjacent to a tubular connecting piece on the side of a patient and, therefore, the priming operation does not require a lot of time. However, the injector has the drawbacks that it creates an obstruction because the portion thereof adjacent to the patient is large, flow rate is varied by the influence of the body temperature of the patient, and the like. The liquid medicine continuous injector of Japanese Unexamined Patent Publication No. JP-A-5-237194 does not cause the above-described problems since the flow rate control tube is provided at a position remote by at least 30 cm or more from a connecting end disposed on the downstream side of the tube. However, it has the drawback that a lot of time is required for priming a tube downstream from the flow rate control tube since the tube is constituted by a tube having a very small inner diameter.